Neural interfaces have emerged as possible interventions to reduce the burden associated with some neurological diseases, injuries, and disabilities, such as spinal cord injuries which can cause reduced sensation and mobility by damaging the nerve pathways between the brain and the rest of the body. Many neural interfaces take advantage of cortical plasticity, which is the brain's ability to reorganize its functions and their locations within the brain in response to chronic changes in the received sensory information.
Researchers have considered implanting electrode devices to detect nerve signals or stimulate nerves. For example, signals detected in the brain or peripheral nervous system may be used to help control devices outside the body, such as cursors on a computer screen or prostheses; cochlear implants for the deaf stimulate auditory nerves in response to sounds; and stimulation of the spinal cord has been considered for restoring genitourinary and bowel motor functions. Studies of spinal cord recording include:
Borisoff J. F., McPhail L. T., Saunders J. T., Birch G. E., Ramer M. S., Detection and classification of sensory information from acute spinal cord recordings. IEEE Transactions on Biomedical Engineering. 53(8):1715-9, 2006.
Sahin M., Information capacity of the corticospinal tract recordings as a neural interface. Annals of Biomedical Engineering. 32(6):823-30, 2004.
Patton H. D. and Amassian V. E., Single and multi unit analysis of cortical stage of pyramidal tract activation. Journal of Neurophysiology. 17:345-63, 1954.
For persons suffering from paralysis due to spinal cord injury, attempts to restore motor function have relied on retraining any undamaged nerve pathways and stimulating nerves with signals generated independently of brain signals. Studies of spinal cord stimulation include:
Philip Troyk, Martin Bak, Joshua Berg, David Bradley, Stuart Cogan, Robert Erickson, Conrad Kufta, Douglas McCreery, Edward Schmidt, and Vernon Towle. A Model for Intracortical Visual Prosthesis Research. Artificial Organs. 27(11):1005-1015, 2003.
Jonathan Coulombe, Sylvain Carniguian, and Mohamad Sawan, A Power Efficient Electronic Implant for a Visual Cortical Neuroprosthesis, Artificial Organs. 29(3):233-238. 2005.
Rajiv Saigal, Costantino Renzi, and Vivian K. Mushahwar, Intraspinal Microstimulation Generates Functional Movements After Spinal-Cord Injury, IEEE Transactions on Neural Systems and Rehabilitation Engineering, Vol. 12, No. 4, 2004.
Victor Pikov and Douglas B. McCreery, Mapping of Spinal Cord Circuits Controlling the Bladder and External Urethral Sphincter Functions in the Rabbit. Neurourology and Urodynamics 23:172-179 (2004).
Douglas McCreery, Victor Pikov, Albert Lossinsky, Leo Bullara, and William Agnew, Arrays for Chronic Functional Microstimulation of the Lumbosacral Spinal Cord. IEEE Transactions on neural systems and Rehabilitation, Vol. 12, No. 2, 2004.
Changfeng Tai, August M. Booth, Charles J. Robinson, William C. de Groat, and James R. Roppolo, Isometric Torque About the Knee Joint Generated by Microstimulation of the Cat L6 Spinal Cord. IEEE Transactions on neural systems and Rehabilitation, Vol. 7, No. 1, 1999.
Lisa Guevremont, Costantino G. Renzi, Jonathan A. Norton, Jan Kowalczewski, Rajiv Saigal, and Vivian K. Mushahwar, Locomotor-Related Networks in the Lumbosacral Enlargement of the Adult Spinal Cat: Activation Through Intraspinal Microstimulation. IEEE Transactions on neural systems and Rehabilitation, Vol. 14, No. 3, 2006.
Changfeng Tai, August M. Booth, Charles J. Robinson, William C. de Groat, and James R. Roppoloa, Multi-joint movement of the cat hindlimb evoked by microstimulation of the lumbosacral spinal cord. Experimental Neurology 183 (2003) 620-627.
M. M. Pinter, F. Gerstenbrand, and M. R. Dimitrijevic, Epidural electrical stimulation of posterior structures of the human lumbosacral cord: 3. Control of Spasticity. Spinal Cord (2000) 38, 524-531.
B. Jilge, K. Minassian, F. Rattay, M. M. Pinter, F. Gerstenbrand, H. Binder, M. R. Dimitrijevic. Initiating extension of the lower limbs in subjects with complete spinal cord injury by epidural lumbar cord stimulation. Exp Brain Res (2004) 154: 308-326
K. Minassian, B. Jilge, F. Rattay, M. M. Pinter, H. Binder, F. Gerstenbrand and M. R. Dimitrijevic, Stepping-like movements in humans with complete spinal cord injury induced by epidural stimulation of the lumbar cord: electromyographic study of compound muscle action potentials. Spinal Cord (2004) 42, 401-416.
However, these stimulation therapies may not be effective for persons suffering from complete spinal cord injuries, when no motor function or sensation remains below the injury site, or for restoring more complex motor functions and skills such as standing up and walking. Therefore, a need remains for a device that enhances or restores motor function for persons suffering from spinal cord injuries, including more severe injuries such as complete spinal cord injuries.